In 1714, England's Parliament offered a huge reward to anyone whose method of measuring longitude could be proven successful. The scientific establishment -- from Galileo to Sir Isaac Newton -- had mapped the heavens in its certainty of a celestial answer. In stark contrast, one man, John Harrison, dared to imagine a mechanical solution -- a clock that would keep precise time at sea, something no clock had been able to do on land. And the race was on.

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